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Topic: Dimension command - multiplier m (Read 7619 times)

The problem is that the units multiplier has two functions, not one. You are thinking of it only as a drawing units conversion (feet to millimeters, etc.). Maybe that is how you have always thought of it but that is not how it has been described in past user manuals. It was just a multiplier for whatever value is measured, for whatever reason you want to use it.

In other words, it is also a SCALE multiplier. I have used it that way since it was added to the program. So If I select a part of a drawing, copy it and scale it 4X I can use a multiplier of 1/4X (0.25) to cause the displayed dimension to be correct in the enlarged detail. This is a standard mechanical drawing practice that dates back to before DesignCAD and I am pretty sure that is why the multiplier was introduced to the program in the first place (long before you had a choice of drawing units).

I have understood the schizophrenic nature of the multiplier since day one - some people use it for one thing and some use it for another. In fact, buy doing the appropriate math you can use it to scale a dimension and convert it to different measurement units.

However, disabling the multiplier when drawing units are defined defeats the original purpose of the multiplier. I do not see why it has to be disabled. If a drawing unit has been defined just make the multiplier default to 1. Then if someone desires to include a scaled detail it will still work.

on my side, I think that, indeed, if you have units enabled in dimmensions-settings, yes, of course, you can not (I would say you must not) enable the multiplier, because, if not, the result will be totaly fanciful.

If you want to use the multiplier, as DT said, just don't specify a unit in the dimension and add your own suffix with the suffix tools : it's totaly logical.

I simply cannot understand what JJG and Rob are saying. Obviously they do not understand me.

Let's say I have a drawing that has millimeters set as the drawing units.

Now I draw some dimensions, showing the distances in millimeters.

Next I want to create a "Detail." If you don't know what Detail means in a mechanical/engineering/architectural drawing, you should go back to school! But, to save time, here is a definition from "Websters Third New Internationsl Dictionary:"

"detail drawing n : a separate large-scale drawing of a small part of a machine or structure; ..."

See the attached image for an example.

So I select a small part of my drawing and duplicate it (N) to the side of the whole drawing. Next I select it and use "Edit/Selection Edit/Scale" to scale the detail 5X. Now it is possible to see the fine details (hence the name "detail drawing") that cannot be seen easily in the entire drawing.

If I now use the dimension function to measure a part of the expanded drawing it will produce the wrong dimension (shown in red).

Remember, it is not the drawing we are trying to dimension, but the thing represented by the drawing.

If I create a dimension and set the Units Multiplier = 1/5 or 0.2 the dimension shows the correct distance (in black).

Is there anyone who cannot understand this?

****

Now, if you understand the principle, please give me a rational argument why the program should prevent you from doing this with drawings that have assigned drawing units?

Do not give me nonsense that "Units Multiplier" is "supposed" to be used to change drawing units. Who says? Just because that it the way you have used it in the past? Nonsense! I have used it for that purpose, and I have used it for the original intent - to scale dimensions to match the scale of details.

Can you give me any rational reason why it should not continue to be used for details in drawings that have assigned units? After all, you can assign units to a dimension that are different from the drawing units (inches in a millimeter units drawing). So the only remaining purpose of the "Units Multiplier" is the original purpose - to scale dimensions to match detail scale.

Why would you want to eliminate this feature? Rational arguments only, please! This cripples DesignCAD so it can no longer be used for a common drawing practice - that doesn't make sense to me!

DR Pr, YOU CAN STILL DO THAT, even with drawings with assigned units! You just can't ALSO get it to auto-apply the units suffix to the multiplied dimension (even if you check the box). In your image, you're not even specifying the suffix, so I don't see the reason for your dissatisfaction.

See attached drawing.

Can you draw objects to actual scale and dimension them correcty? Check.Can you create detailed section views that are scaled up and dimension them correctly (in the same base unit) by using a multiplier? Check.

Can you dimension these scaled details in SOME ALTERNATE DIMENSION UNIT by a combination of different dimension unit and multiplier? No -- you have to manually calculate the multiplier to account for both the change in scale AND the unit change -- just as you would have all along. So you can't dimension that scaled up section, which is based in millimeters, in inches by choosing the "inches" dimension unit and a multiplier of 5; you have to use 5/25.4 as your multiplier instead.

I simply cannot understand what JJG and Rob are saying. Obviously they do not understand me....Phil

DT has explained that "we must distinguish between the DRAWING's unit base (unitless, feet, inches, m, cm mm) and the DIMENSION's selected measurement unit."and he precise : "And you can still do that -- just don't specify a unit in the dimension ; add your own suffix with the suffix tools."

also, just don't specify a unit in the dimension, and all works correctly, as you think it.

Of course, like you, I draw sometimes some details, at 1/10 or other. but never I specify a unit in the dimension-command. because, for example, if a dimension is "1340", I let it as "1340", and not as "1340 mm" ... do you understand now the difference ? So I can use the multiplier.

I think what you don't understand, is that you must not specify a unit in the dimension-setting, what is completly different with DRAWING's unit base.

1. I typically do not specify a dimension suffix for all dimensions in a drawing. I usually place a statement that dimensions are in XX unless specified otherwise. This allows me to use larger fonts in tight spaces. So, no, there are no dimensions in the example.

2. However, if I want to create a detail and use a different unit in a dimension, why shouldn't this work?

Note: I did not ask why it doesn't work. Why should a scaled dimension work any differently than a non-scaled dimension? Again, I am not asking why it doesn't work. I am asking for a rational explanation why one dimension should work one way and another work a different way. Does this make sense?

3. In case you missed the point, let me say it another way.

Suppose you want to use a specific suffix in all dimensions in a drawing - say mm - and you have specified a specific drawing unit - again, millimeters. Great, you are happily drawing away and scatering dimensions all over the drawing. But when you dimension a scaled detail using a unit other than the drawing unit either

1. The dimension unit suffix works but the multiplier does not

or

2. The multiplier works but the dimension unit suffix does not

or

3. Some other screwball combination.

Why shouldn't all features work at the same time?

And, if a user wants to dimension a scaled detail in a unit different from the drawing units, why should the user have to calculate the units difference (that's what the dimension units are supposed to do) and multiply it by the detail scale (units multiplier) and then manually enter a suffix?

****

The reason dimension units were added to the program was to make it easier to dimension in different units, and to do the calculations automatically to reduce user error. Right?

The purpose of the units multiplier is to scale the value shown in the dimension text. Right?

The purpose of the suffix is to show the units of the dimension. Right?

So what rational reason is there for saying some combinations work part of the time, other combinations work some other times, and if you want to use this feature you can't use that?

It seems to me that if all of this worked correctly there would be no difference between scaled and unscaled dimensions and this argument would have never come up.

Sorry, I'm not going to go into whys and why-nots. We always have to pick and choose our targets based on factors such as time and effort required, overall utility of the result, and the priority of that effort and benefit over other issues we could choose to address.

As things currently stand, the dimension auto-suffix is only going to work reliably with to-scale objects. The auto-suffix depends on DesignCAD's being able to reliably determine how to convert from one measurement unit to another. Within those limitations, it works quite reliably.

Once you step outside those limitations, such as by trying to dimension stuff at some arbitrary scale with some arbitrary unit, you're just going to have to add in the suffix and calculate the multiplier yourself.

I've agreed that the inability to specify a custom suffix in a macro is broken and needs to be fixed. We'll definitely look into that. Supporting arbitary combinations of scaling and unit conversion, however, is something we'll have to think on. It may have unintended ripple effects throughout the entire dimensioning domain, which has seen quite enough ripple effects for a while. Maybe it'll be easy, maybe not. I honestly don't know right now.

That's where I'm leaving the conversation for now. I'll review further posts, but probably won't have anything to add for some time.

I certainly agree that there are more important fish to fry. And, like you, I cringe at the thought of unexpected side effects when major changes are undertaken. But, if you ever run out of things to do ...

many thanks for the impressive work You have put into explaining the complicated dimension-command in such an understandable way.But honestly: wouldn't it be easier and better, to abandon the unnessesary restriction of the multiplier in connection withunit bases (feet, inches, m, cm, mm etc.) and go back to <Multiplier m [-1 (and any value <= 0) = off, any positive value turns it on].

Additionally we would save ourselves a lot of pain if <PrefixText p$ <SuffixText s$would work as it did before.

This way users could use an arbitrary unit base and dimension, while at the same time having the same choices in BasicCad that DesignCAD offers in the main program.

Moving to the metric system would certainly be too much to ask, but I for one would welcome it.

That actual SDK automatically should be delivered with every new version of DC, however, is a serious suggestion of me.